Field of the Invention
The present invention relates to a laser processing apparatus that carries out laser processing for a workpiece such as a semiconductor wafer held by a chuck table.
Description of the Related Art
In a semiconductor device manufacturing process, plural regions are marked out by planned dividing lines arranged in a lattice manner on a surface of a semiconductor wafer having a substantially circular disc shape and devices such as integrated circuits (ICs) and large-scale integrations (LSIs) are formed in these marked-out regions. Then, by cutting the semiconductor wafer along the planned dividing lines, the regions in which the devices are formed are divided to manufacture individual semiconductor device chips.
As a method for dividing the wafer such as the semiconductor wafer along the planned dividing lines, the following technique has been put into practical use. Specifically, the wafer is irradiated with a pulse laser beam having such a wavelength as to be absorbed by the wafer along the planned dividing lines to carry out ablation processing and form laser-processed grooves. Then, the wafer is split by giving an external force to the wafer along the planned dividing lines along which the laser-processed grooves serving as the origin of breakage are formed.
A laser processing apparatus that carries out the above-described laser processing includes a chuck table that holds the workpiece, laser beam irradiating means that irradiates the workpiece held by this chuck table with a laser beam, moving means that moves the chuck table and the laser beam irradiating means relatively, and alignment means that detects the region in which processing should be carried out in the workpiece held by the chuck table (for example, refer to Japanese Patent Laid-open No. 2006-253432).